The Wild Years, by Donald Barr Chidsey (epub/Kindle/pdf)
On the pleasure boats of the Old Mississippi, passions ran high when men gambled for the favors of beautiful women -- and renegades carried off girls along with other loot.
Disguised as a notorious outlaw, hot-blooded Dave Macdonough invaded the river rogues' hideout in a reckless attempt to destroy them. But his mission became an act of persona! vengeance when he met the lovely swamp water girl who was their captive mistress.